1. Field of the Invention
The present invention relates generally to a barrier mechanism, and more particularly to a mechanism for moving a slidable lens barrier that is disposed in front of a taking lens in order to protect a photographing optical system of a camera or the like.
2. Description of Related Art
A variety of lens barrier mechanisms for a camera has already been proposed. For example, Japanese Patent Provisional Publication No. 7-168253 discloses a barrier moving mechanism that rotates a barrier within a plane perpendicular to a taking optical axis in such a manner as to prevent the barrier from going beyond the front area of a camera body while the barrier is being opened or closed. Japanese Patent Provisional Publication No. 7-225409 discloses a barrier mechanism that positions a shielding blade, which is movable forward and backward along an optical axis, in front of the end face of the lens while the barrier is closed, and withdrawing the blade from an effective optical path and moving back the blade so that at least a part of the blade can be positioned behind the end face of the lens while the barrier is opened.
The barrier moving mechanism in Japanese Patent Provisional Publication No. 7-168253, however, slides the barrier within the plane perpendicular to the optical axis of the lens, and this requires a space for containing the barrier at the periphery of the lens and thus swells the lens peripheral part. This makes it difficult to downsize the camera and restricts the design. The barrier mechanism of the Japanese Patent Provisional Publication No. 7-225409 is so completed as to require a number of parts.
It is therefore an object of the present invention to provide a barrier mechanism that makes the lens periphery of a camera even by effectively containing a barrier in a space of the lens periphery with a simple structure without increasing the number of parts and enlarges the freedom of design.
To achieve the above-described object, the present invention is directed to a barrier mechanism comprising: a barrier member capable of moving between a closed position for covering a front face of a taking lens and an open position behind said closed position, said barrier member is withdrawn to said open position from the front face of said taking lens; and a guide device that guides said barrier member from said closed position to said open position along a curved track which is described by projecting a moving locus of said barrier member on a plane perpendicular to an optical axis of said taking lens.
According to this invention, the barrier member is moved from the closed position to the open position along the curved track formed by the guide device. Thus, the barrier member can be contained in a relatively small space at the peripheral part of the taking lens in the barrier open state, and this downsizes the camera.
To achieve the above-described object, the present invention is directed to a barrier mechanism comprising: a barrier member capable of moving between a closed position for covering a front face of a taking lens and an open position behind said closed position, said barrier member is withdrawn to said open position from the front face of said taking lens; a lever member integrated with said barrier member or integrally connected with said barrier member; a support shaft that tiltably supports said lever member; a rotary member rotatably attached to the circumference of said support shaft and rotating by a driving force; a connecting member that connects said rotary member and said lever member, one end of said connecting member being secured to said rotary member and the other end being loosely attached to said lever member; and a guide device that regulates the movement of said barrier member moved by a driving force transmitted through said connecting member and said lever member to guide said barrier member from said closed position to said open position.
According to this invention, the lever member integrated with the barrier member is supported about the support shaft in such a manner as to rotate freely, and the lever member loosely connects to the connecting member. For this reason, the barrier member can be positioned arbitrarily, and the guide device regulates the movement of the barrier member. According to this invention, the barrier member can be moved along the curved surface by the simple structure. The barrier member can be moved along a curved surface desired by a designer according to the design of the guide device, and this increases the freedom of camera design.